1. Field of the Invention
The present invention relates to a method and apparatus for driving a plasma display panel used for displaying images in a television set or a computer monitor, and more particularly, to a method and apparatus for driving a plasma display panel, which can improve the image contrast by suppressing excessive discharges during a reset period.
2. Description of the Related Art
Contrast is an important factor affecting the quality of an image produced by a plasma display panel (PDP). Contrast is represented by the ratio of the brightness of a bright portion to the brightness of a dark portion in a picture displayed on a panel. The bright portion mainly comes from light generated by a sustain discharge, and the dark portion comes from light generated by a reset discharge. It is necessary to increase the brightness of the bright portion or decrease the brightness of the dark portion in order to enhance the contrast. The driving period of a PDP is divided into a reset period, an address period, and a sustain period. The reset period most greatly influences the brightness of the background image of a panel. Conventionally, with a sustain electrode at a ground voltage, a voltage which slowly increases is applied to a scan electrode to form negative wall charges on the scan electrode. Positive wall charges on an address electrode are formed due to a consecutive weak discharge between the scan electrode and the sustain electrode. Thereafter, the voltage applied to the scan electrode is slowly decreased, thereby decreasing the wall charges which have excessively been formed on the electrodes. However, according to a conventional method, a discharge occurring between the scan electrode and the sustain electrode during the reset period increases the background brightness, thereby decreasing the contrast.